libext2fs: fix potential divide by zero bug caused by a lxcfs bug

If sysconf(_SC_NPROCESSORS_CONF) returns zero, this can cause a divide by zero. Make ext2fs_rw_bitmaps() more robust defaulting to 4 threads if _SC_NPROCESSORS_CONF returns an invalid value. #114 Signed-off-by: Theodore Ts'o <[email protected]>
tytso · May 2, 2024 · b88b3b4 · b88b3b4
1 parent 66b0b3c
commit b88b3b4
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c
@@ -557,7 +557,7 @@ errcode_t ext2fs_rw_bitmaps(ext2_filsys fs, int flags, int num_threads)
 	 * MacOS, FreeBSD, etc.
 	 * ref: https://stackoverflow.com/questions/150355
 	 */
-	if (num_threads < 0)
+	if (num_threads <= 0)
 		num_threads = 4;
 
 	if ((unsigned) num_threads > fs->group_desc_count)